Increased Intracranial Pressure


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Increased Intracranial Pressure

  2. 2. <ul><li>INTRACRANIAL PRESSURE </li></ul><ul><ul><ul><li>is the pressure exerted by the cranium on the brain tissue, cerebrospinal fluid (CSF), and the brain's circulating blood volume </li></ul></ul></ul><ul><ul><ul><li>constantly fluctuating in response to activities such as exercise, coughing, straining, arterial pulsation, and respiratory cycle </li></ul></ul></ul><ul><ul><ul><li>measured in millimeters of mercury (mmHg) </li></ul></ul></ul><ul><ul><ul><li>at rest, is normally 7–15 mmHg for a supine adult </li></ul></ul></ul><ul><ul><ul><li>becomes negative (averaging −10 mmHg) in the vertical position </li></ul></ul></ul>
  3. 3. <ul><li>Cerebral Dynamics </li></ul><ul><li>Cerebrospinal Fluid (CSF) </li></ul><ul><ul><ul><li>a. production </li></ul></ul></ul><ul><ul><ul><li>produced in choroid plexuses of lateral, third and fourth ventricles </li></ul></ul></ul><ul><ul><ul><li>produced at rate of 500 cc/day or approximately 20cc/hour </li></ul></ul></ul><ul><ul><ul><li>eliminated by being absorbed into the arachnoid villi --> dural sinus --> jugular system </li></ul></ul></ul><ul><ul><ul><li>b. circulation </li></ul></ul></ul>
  4. 4. <ul><li>Cerebral Blood Flow (CBF) </li></ul><ul><ul><ul><ul><li>750 mL/minute which is 15% of the cardiac output </li></ul></ul></ul></ul><ul><li>Autoregulation </li></ul><ul><ul><ul><ul><li>pressure autoregulation </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>arterioles dilate or constrict in response to changes in BP and ICP in order to maintain a constant CBF </li></ul></ul></ul></ul></ul>
  5. 5. <ul><li>b. metabolic autoregulation </li></ul><ul><ul><ul><li>arterioles dilate in response to potent chemicals that are by-products of metabolism such as lactic acid, carbon dioxide and pyruvic acid </li></ul></ul></ul><ul><ul><ul><ul><ul><li>CO2 is a potent vasodilator </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>increased CO2/decreased BP --> vasodilation </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>decreased CO2/increased BP --> vasoconstriction </li></ul></ul></ul></ul></ul>
  6. 6. PATHOPHYSIOLOGY <ul><li>Causes of increased intracranial pressure can be classified by the mechanism in which ICP is increased: </li></ul><ul><li>mass effect such as brain tumor, infarction with oedema, contusions, subdural or epidural hematoma, or abscess all tend to deform the adjacent brain. </li></ul><ul><li>generalized brain swelling can occur in ischemic-anoxia states, acute liver failure, hypertensive encephalopathy, pseudotumor cerebri, hypercarbia, and Reye hepatocerebral syndrome. These conditions tend to decrease the cerebral perfusion pressure but with minimal tissue shifts. </li></ul><ul><li>increase in venous pressure can be due to venous sinus thrombosis, heart failure, or obstruction of superior mediastinal or jugular veins. </li></ul><ul><li>obstruction to CSF flow and/or absorption can occur in hydrocephalus (blockage in ventricles or subarachnoid space at base of brain, e.g., by Arnold-Chiari malformation), extensive meningeal disease (e.g., infectious, carcinomatous, granulomatous, or hemorrhagic), or obstruction in cerebral convexities and superior sagittal sinus (decreased absorption). </li></ul>
  7. 7. Elevation in ICP can be graded as follows:   Normal ICP                             0 - 15mm Hg Mile elevation                           16 - 20 mm Hg Moderate elevation                   21 - 30 mm Hg Sever elevation             31 - 40 mm Hg Very severe elevation            41 mm Hg and above   SIGNS AND SYMPTOMS <ul><li>Early Signs </li></ul><ul><li>decreased level of consciousness, confusion, restlessness, lethargy, difficulty with memory and thinking </li></ul><ul><li>pupillary dysfunction </li></ul><ul><li>changes in vision </li></ul><ul><li>deterioration of motor function </li></ul><ul><li>Headache, personality changes </li></ul><ul><li>decreasing Glascow Coma Score </li></ul><ul><li>  </li></ul>
  8. 8. <ul><li>Later Signs </li></ul><ul><li>continued decrease in level of consciousness (stuporous, comatose) </li></ul><ul><li>dilated pupils, no reaction to light </li></ul><ul><li>hemiplegia that progresses </li></ul><ul><li>vomiting </li></ul><ul><li>bradycardia </li></ul><ul><li>hyperthermia </li></ul><ul><li>papiledema </li></ul>
  9. 9. <ul><li>Late changes include: </li></ul><ul><li>  </li></ul><ul><li>Decreased LOC with difficulty to arouse and further decrease in the Glascow Coma Score.  More stimulation will be required to elicit any type of response. </li></ul><ul><li>Pupils will become unilaterally enlarged progressing to fixed and dilated.  Eventually becoming bilaterally fixed and dilated with noted papilledema. </li></ul><ul><li>Decorticate  or decerebrate posturing to flaccidity will occur. </li></ul><ul><li>Patient may only posture to painful stimuli. </li></ul><ul><li>Speech may be absent with only moaning. </li></ul><ul><li>Respiration will be irregular advancing to Neurogenic hyperventilation and respiratory arrest. </li></ul><ul><li>Loss of corneal and gag reflexes. </li></ul><ul><li>Abnormal reflexes such as positive Babinski reflex. </li></ul><ul><li>Vital signs will present the &quot;Cushing triad&quot;. </li></ul><ul><li>hypertention, bradycardia, widening pulse pressure </li></ul>
  10. 10. INTERVENTIONS FOR THE PATIENT WITH INCREASED ICP <ul><li>Goals of Therapy </li></ul><ul><li>Maintain cerebral perfusion pressure. </li></ul><ul><li>b. Prevent focal or global cerebral ischemia and focal brain compression </li></ul><ul><li>Nursing Management includes: </li></ul><ul><li>  </li></ul><ul><li>Maintain the patients head midline to facilitate blood flow. </li></ul><ul><li>Maintain the head of the bed at 30 - 45 degrees to facilitate venous drainage. </li></ul><ul><li>Avoid activities that can increase ICP such as suctioning or gagging. </li></ul><ul><li>Treat hyperthermia as it increases the metabolic needs of the brain. </li></ul><ul><li>Decrease environmental stimuli which can increase ICP. </li></ul>
  11. 11. <ul><ul><li>6. Dim all lights </li></ul></ul><ul><ul><li>7.Speak softly </li></ul></ul><ul><ul><li>8.Touch gently and only when needed </li></ul></ul><ul><ul><li>9. Space all interventions </li></ul></ul><ul><ul><li>10. Limit noxious stimuli such as suctioning to only as needed </li></ul></ul><ul><ul><li>11. Maintain fluid balance via accurate I & O.  Overhydration will lead to cerebral edema. </li></ul></ul><ul><ul><li>12.Monitor electrolytes as these patients are prone to hypernatremia, hypoglycemia, and hypokalemia with diuretic useage. </li></ul></ul><ul><ul><li>13. Monitor hyperventilation to maintain CO2 levels at 25 - 35mm Hg to prevent vasodilation. </li></ul></ul><ul><ul><li>  </li></ul></ul><ul><li>  </li></ul>
  12. 12. <ul><li>Medical Management includes: </li></ul><ul><li>  </li></ul><ul><ul><ul><li>Anticonvulsant therapy for seizures. </li></ul></ul></ul><ul><ul><ul><li>Use of diuretics such as Mannitol, Urea, and Glycerol. </li></ul></ul></ul><ul><ul><ul><li>Barbiturate Coma Therapy to decrease the metabolic demands of the brain. </li></ul></ul></ul><ul><ul><ul><li>50% Dextrose solution if hypoglycemia is present and persistent. </li></ul></ul></ul><ul><ul><ul><li>5. Surgical decompression </li></ul></ul></ul><ul><ul><ul><li>-         considered life saving measure </li></ul></ul></ul><ul><ul><ul><li>-         opening of the skull can lead to severe herniation </li></ul></ul></ul>
  13. 13. <ul><li>Specific Treatment </li></ul><ul><ul><ul><li>Surgical removal of intracranial masses. </li></ul></ul></ul><ul><ul><ul><li>b. Placement of extraventricular drain (temporary). </li></ul></ul></ul><ul><ul><ul><li>c. Placement of VP shunt (usually permanent). </li></ul></ul></ul>
  14. 14. <ul><li>b. Fluid Restriction </li></ul><ul><ul><ul><li>restrict fluids to 65-75% of normal maintenance fluids </li></ul></ul></ul><ul><ul><ul><li>2. use 0.9% NS when possible </li></ul></ul></ul><ul><ul><ul><li>3. D5W may decrease osmolarity of the blood and increase cerebral edema; may cross BBB and negate effect </li></ul></ul></ul><ul><li>c. Hypothermia </li></ul><ul><li>d. Elevation of the Bed </li></ul><ul><ul><li>1. raise the head of the bed 25-30 degrees to promote intracranial drainage </li></ul></ul><ul><ul><li>2. promotes venous drainage </li></ul></ul><ul><ul><li>3. avoid compression of jugular veins or kinking of the neck </li></ul></ul>
  15. 15. Pharmacologic Methods <ul><li>Osmotic Diuretics </li></ul><ul><ul><li>Mannitol </li></ul></ul><ul><ul><ul><ul><li>MOA: reduces the water content of the brain due to the establishment of an osmotic gradient between the brain and the intravascular compartment. Mannitol is a large molecule and will not cross the BBB. </li></ul></ul></ul></ul><ul><ul><ul><li>  </li></ul></ul></ul><ul><ul><ul><ul><li>b. Dosage: 50 – 200 Gm (1 Gm/kg) IV over 24 hours </li></ul></ul></ul></ul><ul><ul><ul><ul><li>                   Titrated to maintain urine output at 30 – 50cc/hr. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>           </li></ul></ul></ul></ul><ul><ul><ul><ul><li>c. Contraindications: </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Patients with anuria related to renal disease, pulmonary edema, severe dehydration, or active intracranial bleeding. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>d. Usually used with Lasix 0.5mg/kg. </li></ul></ul></ul></ul>
  16. 16. <ul><ul><ul><li>e. Nursing Implications: </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Assure foley patency </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Preassessment of patients cardiovascular status </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Monitor electrolytes frequently : serum and urine osmolarity, serum and urine electrolytes </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Always use a filtered needle due to crystallization of the drug </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>An administration set with a 0.22 micron filter must be used </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Available iv as 20% solution (100 gm in 500 ml of d5w) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Must be kept warm or will precipitate </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Adverse effects: chf, pulmonary edema, kidney failure </li></ul></ul></ul></ul></ul>
  17. 17. <ul><li>2. Glycerol </li></ul><ul><ul><ul><li>MOA: reduces CSF production along with osmotic effects </li></ul></ul></ul><ul><ul><ul><li>Dose: 0.5 to 1.0 gm/kg Q 4-6 hours; do not exceed 0.2-1.0 gm/kg/hour </li></ul></ul></ul><ul><ul><ul><li>give IV as a 10-20% solution in 0.45% or 0.9% saline over several hours (3-5 hours) </li></ul></ul></ul><ul><ul><ul><li>Side Effects: rate-related; reduced with slow infusion </li></ul></ul></ul><ul><li>Nursing Implications: </li></ul><ul><ul><ul><ul><li>Slow acting </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Can be used long-term </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Metabolized by the body producing energy </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Mix with iced lemon or juice </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Monitor electrolytes due to diuresis </li></ul></ul></ul></ul>
  18. 18. <ul><li>b. Loop Diuretics- Furosemide, Ethacrynic Acid </li></ul><ul><ul><ul><li>MOA: inhibit sodium and chloride resbsorption in the loop of Henle resulting in contraction of the blood volume which may mobilize cerebral edema </li></ul></ul></ul><ul><ul><ul><li>2. usually administered with mannitol to increase the therapeutic effect </li></ul></ul></ul><ul><ul><ul><li>3. Dose: 0.5 to 1.0 mg/kg prn </li></ul></ul></ul><ul><ul><ul><li>4. Side Effects: hypokalemia, dehydration, hypotension, glucose intolerance </li></ul></ul></ul>
  19. 19. <ul><li>c. Corticosteroids </li></ul><ul><ul><ul><li>1. only proven to be effective in reducing cerebral edema associated with brain tumors; role in traumatic cerebral edema is uncertain </li></ul></ul></ul><ul><ul><ul><li>2. MOA: exact mechanism unknown; may decrease CSF production and stablize brain cell membranes </li></ul></ul></ul><ul><ul><ul><li>3. Dose: dexamethasone most commonly used; 10 mg IV/IM followed by 4 mg IV/IM Q 6 hrs </li></ul></ul></ul><ul><ul><ul><li>4. Side Effects: hyperglycemia, GI bleeding, increased infection risk </li></ul></ul></ul>
  20. 20. <ul><li>End of discussion </li></ul>